Skip to main content
 Previous Next
  • Zoom In (+)
  • Zoom Out (-)
  • Rotate CW (r)
  • Rotate CCW (R)
  • Overview (h)
Geology of Siberia: Encyclopedia Arctica Volume 1: Geology and Allied Subjects
Stefansson, Vilhjalmur, 1879-1962

Geology of Siberia

(EA-I. (V. A. Obruchev)

GEOLOGY OF SIBERIA

CONTENTS
Page
The West Siberian Lowland 4
Northern Kazakhstan 6
The Altai-Saian region 11
The Kuznetsk Alatau and the Shoria Upland 13
The Salair Ridge 14
The Kuznetsk coal basin 15
The Altai 17
The Western Saian 19
The Minusinsk Depression 20
The Siberian Platform 22
The Yenisei Ridge 26
The Taimyr Peninsula 27
The Eastern Saian 28
The Baikal Sh i eld, the Aldan shield, the Stanovoi
Mountains, and the Eastern Transbaikal
29
The Cisbaikal 30
The Baikal Upland 32
The western Trensbaikal 33
The Aldan Plateau 36
The Stanovoi Mountains 37
The eastern Trensbaikal 38
-cont’d-

Geology of Siberia
(V. A. Obruchev)

Contents -#2
Page
The Amur Region and the Southern Maritime Provinces 41
The Amur section 42
The Southern Maritime Provinces 43
Sakhalin Island 45
The Northeastern Region 47
The Verkhoianak-Kolyma section 47
The Chukotka-Anadyr section 51
The Kamchatka Peninsula 53
Bibliography 56

EA-I. (V. A. Obruchev)

GEOLOGY OF SIBERIA
Geological studies of Siberia were less thorough than the investigation
of the Russian Platform, the Urals, and the Caucasus prior to the October
Revolution. A band of some width, along the [ Trans-Siberian - M. E. B. ]
Railway trunk line, was known best; during the period in which the Railway
was built (between 1892 and 1910) several reconnaissance parties, working
from the Urals to Vladivostok, produced a series of maps drawn to scales of
from twenty to forty versts per decimeter. The Altai Mountain region, an
imperial preserve, was studied in rather more detail, but government geologists
were able to produce ten-verst-per - decimeter maps only for the Kuznetsk Basin,
the Salair, the western slope of the Kuznetsk Alatau, and the northern margin
of the Altai before the First World War broke out. Between 1899 and 1913
other geological parties studied the Y e nisei, Lena, Barguzin, and Amur-Maritime
gold areas, and the Minusinak Depression, mapping these areas on a scale of
one or two versts per decimeter.
In 1912 the Geological Survey began to recruit geologists for local studies,
chiefly of the southern belt, in regions possessing features of special interest,
and also in the Viliui and Aldan river basins, Sakhalin, and the Okhotsk and
Anadyr regions. These field parties filled in the outline of geological data
gathered by the Academy of Science of Geographical Society field parties

EA-I. Obruchev: Geology of Siberia

over the vast extent of northern Siberia during a number of years; but their
reports were essentially rather sketchy reconnaissance reports — vast areas
within the regions studied were not examined. Privately sponsored field
parties in the arctic Urals, the Chukotsk Peninsula, and Kamchatka gathered
small amounts of data on these regions at the turn of the century. Thus,
only the southern portions of Siberia had been investigated by geologists
prior to 1917, and even such reconnaissance had not touched the Golodnsia
Steppe of Kazakhstan, the Altai Mountains, and the Western and Eastern Saian,
and these regions remained virtually unexplored. The great northern half of
the country had been crossed only by occasional reconnaissance parties, and
information about the geology of the area was fragmentary and questionable.
It is worthy of note that only two government geologists were maintained
in all of Siberia before the Revolution; one was attached to the Irkutsk Mines
Administration in 1888, and the other to the Tomsk Mines Administration in
1905. Directives drawn up in 1892 indicate that both used St. Petersburg
as their base of operations.
A rapid expansion of Siberian geological studies took place after the
Revolution, and as early as 1919, government geologists who were working in
Siberia were unable to return to St. Petersburg across the Civil War front.
They established permanent headquarters at Tomsk and organized for continuous
research. This developed into the Siberian Geological Survey, which later
became the Siberian Department of the Soviet Geological Survey, and, after
a lapse of several years, was combined with the research organization that
had its headquarters at Irkutsk into the Western Siberian Department of the
Survey. Geological activity, centered at Vladivostok, underwent a similar
development. When the Survey subsequently became the Central Geological

EA-I. Obruchev: Geology of Siberia

Research and Development Institute, these Departments became first Trusts,
and later Geological Administration s ; such Administrations were established
at Semipalatinak and I Y akutsk, and the Khaberovsk Geological Administration
replaced the Far Eastern.
Geologists were attached to a number of organizations in the coal,
petroleum, and ferrous and nonferrous metals field s , and undertook special
tasks there.
The Academy of the Sciences of the U.S.S.R., which led in the study of
the geology of Siberia before the Revolution, continued to send out field
parties for regional stratigraphic, petrographic, geochemical, tectonic, and
geomorphologic studies. The growth of geological research sponsored by the
various geological Administrations and People’s Commissariats was such,
however, that the relative scope of Academy efforts was dwarfed even though
substantial contributions to the study of a number of problems and regions
still came from this source. The efforts of the Russian Geographical Society
in this sphere became insignificant, and research sponsored by private
individuals and concerns disappeared altogether.
The search for mineral deposits of economic importance held top priority
during the Soviet regime’s first decade; this was due to the urgency of in–
dustrial development. The programming of prospecting for Siberia lagged far
behind. Steps were taken to remedy this situation, and a geological map
(1:1,000,000) of the southern portion of Siberia appeared toward the end
of the decade. Maps drawn to larger scales for various regions appeared,
and maps of assorted merit, drawn to a variety of scales, appeared for the
Kuznetsk Basin, the Altai, portions of Kazakhstan, the Minusinek Depression,
the Kuznetsk Al a tau, the Western and Eastern Saian, the Cis-Baikel Cisbaikal , the Lena
region, and Kamchatka.

EA-I. Obruchev: Geology of Siberia

The Geological Map of the Soviet Union (1:2,500,000), published in 1939,
still contained blank spots, but these are growing smaller.
We now turn to the progress of regional geological and tectonic studies.
The West Siberian Lowland occupies the northern half of the area between
the Ural Mountains and the Y e nisei River, and possesses a southward extension —
the Turgai Depression — that lies between the Urals and the Kazakh Steppe.
The fragmentary nature of earlier studies in the area was due to sparse
population and the absence of deposits of the more valuable minerals. The
Soviet period, however, saw considerable progress in the investigation of the
area. Oil possibilities, water supply, potential railway routes, brine lakes,
and peat deposits were studied, as well as moraines and signs of glaciations
in the north, and coal deposits in the Turgai Depression; several geologists
were occupied with those tasks.
The region’s river valleys were investigated, the suspected eastward
extension of the folding and igneous intrusion of Paleozoic strata in the
Urals were established, while well records and geophysical investigations
along railroad routes revealed that the folded Paleozoic underlies slightly
deformed Quaternary, Tertiary, Cretaceous, and Jurassic formations. Escaping
gas and evidence of petroleum have been found at some points.
Several field parties also studied the salt, sod s a , and mineral lakes of
the Kulundim and Barsbin steppes; these investigations brought to light a
great deal of information concerning the processes and conditions of salt
deposition and point to the possible future utilization and development by
chemical industries.
A varied fauna, a not inconsiderable flora, and a large amount of informa–
tion about the Quaternary, Tertiary, local Cretaceous, Jurassic, and Devonian periods

EA-I. Obruchev: Geology of Siberia

were gathered in studies of the deep-out valleys of the Irtysh, the Ob, and
their tributaries.
Several preglacial, glacial, and interglacial stages have been identified
in the regional Quaternary sequence. The Tertiary sequence contains terri–
genous formations of Miocene and Pliocene age, and occasional Paleocene,
Eocene, or Oligocene marine rocks; Cretaceous, Jurassic, Carboniferous, and
Upper Devonian formations, however, crop out only in the Ob Valley above
Novosibirsk. The rich and varied fauna found in the Pliocene rocks near
Pavlodar was described by Orlov.
A number of investigators penetrated the forested and unforested tundra
west of the Ob and along the western tributaries of the Y e nisei by following
the Taz River. They have studied the glacial and interglacial stages, and
the Arctic Marine Transgression of the Gydan ski and Iamal peninsulas. For example,
by mapping the distribution of erratics, Gromov was able to fix the boundary
between the ice sheet moving down from the Urals and the sheet moving from
the highlands beyond the Yenisei River. The southern boundaries of the
component stages of two glaciations (the Riss, the W u ü rm, and possibly of
an earlier one) are still in doubt, as are the locations of the outlets of
ancient lakes that came into being when moraines damned the Ob and Irtysh.
Gromov found an oil-bearing formation of upper Volga age in the area. Studies
were made of the peat deposits and soils of the tundras and well as their
hydrology and geomorphology. Edelshtein integrated the hydrological date.
The Quaternary and upper Tertiary strata in the Turgai Depression were
mapped (Paleocene formations frequently outcrop beneath the latter). The
abundant fauna of the Turgai Paleocene was known in pre-Revolutionary times
from studies at Lake Chelkar and along the Dzhilanchik River.

EA-I. Obruchev: Geology in of Siberia

A. Borisiak of the Academy began to catalogue this fauna at that time, and
he continued the task after the Revolution. Cretaceous and coal-bearing
Jurassic formations crop out locally along the eastern and western borders
of the Depression. The soils and ground water of the Ciz-Aral have been
investigated. Bykov and Baiarunas have described the geology of the area,
and Prigorovski described the coal deposits.
Tectonic investigations in the area have revealed that the Mesozoic
and Cenozoic formations that cover the more intensely deformed Pale o zoic for
great distances eastward are only locally deformed, and this in the vicinity
of the Irtysh and Ob rivers, where extremely broad folds are present. This
folding becomes somewhat more pronounced toward the Urals piedmont, and is
particularly noticeable in the Rhaetic-Liassic coal measures of the Cheliabinsk
Basin, and in the Cretaceous and Jurassic formations north and south of the
Basin, where relatively recent fault movements have brought up Jurassic,
Cretaceous, and Tertiary formations through varying amplitudes.
Northern Kazakhstan (Altai Mountains and mining district omitted). The
geological investigation of this region made great progress after the Revolution
because important mining projects were initiated here, and also because flat
relief and the absence of a forest cover make exploration simple. The region,
consequently, is probably the most thoroughly investigated in all Siberia, in
spite of the fact that the structure is extremely complex. The stratigraphic
column carries representatives of every period from the Archean to the Quaternary,
inclusive, and igneous bodies are abundant. The regional pre-Cambrian is repre–
sented by the Archean (gneisses and mica schists) and the Proterozoic (quartzites,
phyllites, sericitic and gra m phitic schists, marbles, and porphyrites); each
section is divided into two unconformable divisions.

EA-I. Obruchev: Geology in of Siberia

Middle and Upper Cambrian formations that carry trilobite, archaeocynthid,
and brachiopod fauna, and fossil algae make their appearance in limestones and
shales at various localities.
The Ordovician and Silurian sequences are even more complete. They are
represented by beds runging from Osarkian to Downt ow nian age, and carry grap–
tolite, pteropod, brachiopod, coral, and other invertebrate remains; limestones
and shales dominate the lithology.
Extrusive products of submarine volcanism are found together with the
sedimentary Cambrian, Ordovician, and Silurian rocks; thus, fully half the
Cambrian sequence in the Chingiz Range consists of lava analogues which are
also found in central Kazakhstan. The Ordovician also contains tuffs and
volcanic breccias in the latter area, but it is the upper Silurian that contains
the effusives in the Chingiz and Karaganda areas. The volume of effusives in
Tarbagatai and the Ciz-Balkhash is somewhat less.
Recent studies have revealed the extent of Devonian rocks to be smaller
than had been supposed; paleontological studies revealed that much that had
been considered Devonian in pre-Revolutionary times was really Cambrian,
Ordovician, and Silurian. The lithology of the Devonian, however, turned out
to be more diversified than had been supposed previously; the period saw the
deposition of clays, sandstones, conglomerates, lavas, tuffs, and breccias,
as well as shales and limestones. The Devonian sequence contains, however,
terrigenous deposits in addition to the marine sediments and effusive lavas;
these show that portions of the region were raised during the Caledonian
Revolution. This is borne out by the presence of volcanic lava flows, by the
lithology of the sediments, and the character of Devonian flora that made
their appearance early in the period.

EA-I. Obruchev: Geology in of Siberia

A well-developed, richly fossiliferous Carboniferous sequence (that
carries abundant fauna and flora) is represented by marine, lagoonal, and
terrigenous deposits that indicate a continuation and spread of the emer–
gence initiated in Devonian time. (The extent of emergence is measured by
the extent of coal.) The lithology of the Carboniferous is even more
diversified than that of the Devonian; claystones, coals, gypsum, and
limonite appear in the stratigraphic column together with the characteristic
limestone, shales, marls, sandstones, and conglomerates. Lavas, volcanic
breccias, and tuffs of lower and early-middle Carboniferous age are found
throughout the region, but upper Carboniferous extrusives are confined to
it southeastern portion.
Recent studies have established the presence of Permian formations in
Kazakhstan; this series is represented by the Kalbinsk Range coal deposit,
the Kenderlyk oil-shale deposits in the Saur Mountains (these carry a fish
and pelecypod fauna), and the fossil-bearing marine formations on the shores
of Lake Zaisan-Nor. The fish and pelecypod fauna in the copper-bearing
sandstones that lie unconformably upon the Carboniferous rocks in central
Kazakhstan fix the age of the former as Permian.
These Paleozoic faunas and floras were classified and described, in part,
by a number of Soviet paleontologists, including, in particular, Gorski ,
Krishtofovich, Nalivkin, and Nekhoroshev.
No Triassic rocks have been observed in Siberian Kazakhstan, and it is
improbable that any will be found, inasmuch as the Permian marine sediments do
not extend west of points east of Lake Zaisan-Nor. The sea had retreated
eastward, and only embayments reached westward to the Irtysh valley. The
Permian formations are terrigenous over the rest of the region. The Cheliabinsk

EA-I. Obruchev: Geology in of Siberia

Basin coal measures, however, are uppermost Triassic (Rhaetic). The entire
region consisted of dry land through the upper Permian, the Triassic, and
the Jurassic, and it was only in late Jurassic time that a marine trans–
gression moved southward, parallel to the Urals piedmont.
The Jurassic is represented by sandstones, shales, claystones, con–
glomerates, and a variety of plant-bearing coal deposits, as well as the
fossil clays and bauxites of an ancient zone of weathering; these lie here
and there unconformably upon Paleozoic rocks. The cola deposits of Karaganda,
Dzhezkaggan, Kiakta, and Baikonur are of Jurassic age; they lie on top of
Permian rocks at Kenderlyk and at some points west of the Irtysh.
Lower Cretaceous marine formations crop out north of the Aral Sea;
Upper Cretaceous formations crop out along the eastern margins of the Turgai
Depression, and also appear in the vicinity of Pet r opavlovsk on the Depression’s
northern slopes. (This information was discovered by means of drilling.)
In central and eastern Kazakhstan, Cretaceous red conglomerates and finer
grained sedimentary rocks fill ancient valleys and underlie early Cenozoic
formations.
Red, yellow, and white Tertiary conglomerates, sandstones, marls, clays,
kaolins, sands, and gypsums are found in ancient valleys and depressions. In
places these formations form lines of hills (in the vicinity of the Saur
Mountains), or form divides between valleys, as along the Black Irtysh or
in the Golodnaia Steppe (at Bedpak-tala). There are localities, for example,
Mount Ashu-tas along the Irtysh, at which a rich Oligocene-Miocene flora is
found. Other localities carry remains of upper Oligocene, Miocene, and
Pliocane vertebrates, and still other localities carry symptoms of Tertiary
marine conditions.

EA-I. Obruchev: Geology in of Siberia

The regional Quaternary is represented by deltaic, overbank, rainwash,
and stream-bed deposits. These include forest soils, gravels, sands, and
clays of river terraces; as yet, these deposits have not been investigated
thoroughly. Manual remains are found occasionally.
A variety of intrusive bodies and veins connected with a number of
tectonic movements have invaded the pre-Cambrian and Paleozoic formations in
the region. Basic and ultrabasic rocks are the hallmark of the pre-Cambrian
here, and two alkaline granite intrusions associated with two tectonic move–
ments are present. The Salair and Teconic phases of the Caledonian Revolution
were accompanied by the injection of granodiorites, while the upper Silurian
phase saw the injection of great volumes of basic and ultrabasic rocks. Early
Variscan movements were accompanied by granodiorite and biotite-hornblende
intrusions (mid-Carboniferous), while the injected bodies associated with the
later Permian phases of the Variscan orogeny consisted of alkaline granites
and other alkaline rocks (nepheline syenite, te a s chenites, pantellerite,
anorthoclase - rich rock species).
West of the Irtysh these intrusive rocks are replaced by extrusives that
cover the lower Permian terrain, and they may be of lower Mesozoic age. The
only indication of later volcanism is a group of basalt dikes in the Kalbinsk
Range. Other Paleozoic extrusives have been mentioned above; these tend to be
alkaline rather than acid.
The structure of the region is the product of two pre-Cambrian tectonic
movements, four orogenic stages of the Caledonian Revolution, and four orogenic
stages of the Variscan. These structures are the geosynclines, monoclines, and
raised platforms that have characterized the tectonics of Kazakhstan since
Paleozoic time. Zones of folding have been developed in the geosynclines and,

EA-I. Obruchev: Geology in of Siberia

to some extent, upon the monoclines; brachyfolds and domes have been developed
on the monoclines.
Post-Permian vertical oscillations occurred in the Upper Jurassic, in
the mid-Cretaceous after the end of the Turonian epoch, and at the end of
Cretaceous time. The marine waters that commenced their advance from the
north, along the foothills of the Urals, in late Jurassic and early Cretaceous
time, reached Kazakhstan in Tertiary time, and involved the region in the
general downsinking, transforming it into an archipelago. Uplift at the end
of Oligocene time reestablished dry land conditions. All of the movements
associated with the Alpine orogany were vertical oscillations, though fault
movements occurred in some places; these latter continued as late as Pliocene
time, and even into one of the interglacial stages.
It is worthy of note that the dimensions and distribution of the region’s
folded zones is the subject of a dispute between Kassin, who draw the first
tectonic ma n p of Kazakhstan, and Shatski , who used materials gathered by
Academy of Science s field parties to draw a different map.
Gornostaev, Eliseev, Kassin, Nakovnik, Nekhoroshev, Rusakov, Satpaev,
Shligin, Iagovkin, and Iskovlev have made perhaps the most substantial con–
tributions to the study of the geology of the region.
The Altai-Saian region embraces the Altai and Kuznetsk Alatau, the Salair
Mountains, and the Western Saian, and the Kuznetsk and Minusinsk basins that
lie among these ranges. The western boundary of the Altai-Saian region runs
through Novosibirsk district, and the eastern boundary runs through Krasnoiarsk and
Yenieeisk districts. Formerly, this area was known in the most general way,
investigations having been confined to areas that lie along the Trans-Siberian
Railway trunk line. The geologists of the Imperial Geological Survey ascer–
tained the general nature of the Kuznetsk Basin and the mountain ranges that

EA-I. Obruchev: Geology in of Siberia

surround it; Survey geologists also explored various portions of the
Minueinsk Basin and the eastern slope of the Alatau. The Altai mining dis–
trict was known from reports compiled by the district’s many mining engineers,
but the only data on the Altai Mountains and the Western Saian consisted of
reports of infrequent travelers. After the Revolution, however, the geological
investigation of this great and tectonically complex area forged ahead at
greatly increased tempo because of intensive prospecting activity by the
Western Siberian Department of the Soviet Geological Survey (later the
Geological Administration).
Mesozoic and Cenozoic continental deposits, in general, and the great
Jurassic coal series of the Chulym-Yenissisk Basin, in particular, dominate
the flat and gently rolling areas that constitute the northern portions of
the region. The A lower [] Carboniferous Minusinsk series, outcrops beneath
the Jurassic formations along at the southern edges of the basin. Pre-Cambrian, Cambrian,
Silurian, and Devonian deposits, as well as some igneous rock bodies, are
found in an ancient horst structure in the Arga Range near Achinsk, and con–
statute the most important outcrop in the Chulym area. Cambrian, Ordovician–
Silurian, Devonian, and some pre-Cambrian rocks outcrop in the Kemchugsk
Mountains, between Achinsk and Krasnoiarsk. Devonian coals are found on the
western shore of the Yenisei River, southwest of Krasnoiarsk. The Jurassic
formations are overlain by plant-bearing Upper Cretaceous beds at some
localities, and small, widely scattered areas of Tertiary deposits are also
preserved.
West of Tomsk, Taiga, and Novosibirsk, a Carboniferous-Permian coal series,
Upper Devonian and lower Carboniferous marine sediments, and Cretaceous con–
glomerate underlie plant-bearing Tertiary (Eocene and Miocene) and Quaternary

EA-I. Obruchev: Geology in of Siberia

sediments; massive granites outcrop along the Ob near Novosibirsk.
The region’s pre-Cambrian and Paleozoic rocks are intensively deformed,
whereas the Mesozoic and Cenozoic rocks have been subjected to gentle, local,
and shallow folding. Late Variscan granite intrusions are also present.
Korovin’s work on the Yenisei-Chulym Basin is notable, as is Vasilev’s
work on the Arga Range.
The Kuznetsk Al a tau and the Shoria Upland have been quite thoroughly
examined by a number of investigators, because rich mineral deposits (gold and
iron in particular) are present in the area. Pre-Revolutionary investigators
recognized the fact that pre-Cambrian rocks dominate the regional lithology,
and belong to a range of rock types that extends from gneisses to a variety
of schists. During the early years of the Soviet regime, geologists were inclined
to regard all of the pre-Cambrian rocks as metamorphosed Cambro-Ordovician, but
careful studies of excellent outcrops along several of the local rivers revealed
that wisespread Archean rocks, wedged into early Paleozoic formations by compli–
cated tectonic movements, are present, as well as Proterozoic limestones, schists
and extrusives. Rocks formed during all three divisions of the Cambrian period
(Lowe, Middle, and Upper), with their characteristic faunas, as well as Ordovician
rocks and fossil-bearing Silurian rocks, lie atop Archean and algal Proterozoic
rock, and constitute the main mass of the Alatau together with the Shorian Upland.
The rocks of Devonian age, on the other hand, are preserved in some grabens, but
in the main, outcrop with lower Carboniferous formations along the borders of
the Alatau and in the Shorian Upland. A Permian coal series, Jurassic forma–
tions with plant remains, and Tertiary formations are found along the edges
of the Alatau, as well as Jurassic and Tertiary gold-bearing conglomerates.
Records of two glaciations, which include a number of glacial lakes, are found
in the upper Alatau.

EA-I. Obruchev: Geology in of Siberia

The abundant pre-Cambrian and Paleozoic intrusive bodies in the area
consist of pyroxenites, labradorites, gabbros, gabbro-syenites, gabbro–
diorites, granodiorites, granites, and “proterobases.” The region’s
extrusives (melanophyres) are also of pre-Cambrian and Paleozoic age.
The breaks and unconformities between various formations indicate a
number of pre-Cambrian, Caledonian, and Variscan tectonic movements; the
exact number of movements is still in dispute, however.
The first folds observable in the Alatau appeared in pre-Cambrian and
early Paleozoic time; these were washed into shallow Devonian seas. Later
block movements caused folding, intrusion, and extrusion at the margins of
the region.
The work done in this region by Bazhenov, Bulynikov, Derbikov, Kuzmin,
Lebedev, Monich, Radugin, Usov, and Churakov should be noted.
The Salair Ridge is the southwestern margin of the Kuznetsk Basin. Here,
too, more recent prospecting for polymetallic gold, iron, and bauxite deposits
brought about intensive geological exploration. Formations of late Proterozoic,
Cambrian, Ordovician, Silurian, and Lower, Middle and Upper Devonian enter
into the stratigraphy of these mountains; marine lower Paleozoic, marine
lower Carboniferous, and terrigenous middle and upper Carboniferous formations
outcrop at the margins of the ranges. (The last two types are found in the small
Gorlovsk and Eltsov s k coal basins.) Devonian rocks also outcrop at the edges
of the coal basins. Questionable Meso c z oi z c deposits as well as Tertiary lake
deposits are found at some localities in these areas. The entire regional
Paleozoic is intensely deformed and intruded by granites, quartz nordmarkites,
oligoclasite s , albitophyres and diorite-diabases; the Cambrian, Ordovician,
Silurian, and part of the Devonian stratigraphic column include lavas and tuffs.

EA-I. Obruchev: Geology in of Siberia

Materials were also gathered on Quaternary deposits, ancient bau z x it o ic zones
of weathering, soils, and peat deposits.
The complexity of the tectonic structure of the Salair Mountains is
cause for considerable disagreement among geologists. Proterozoic, Caledonian,
and Variscan geosynclinals folding is clearly present. A thrust along which
Cambrian rocks overrode Devonian formations has been identified on the eastern
margins of the area. The fundamental tectonic structure of the area is
presumed to be a great eastward thrust of Sudetian age.
The Devonian and Carboniferous are intensely folded, faulted, and overthrust
in the Gorlovsk Basin. Block faulting occurred in the region during the Cenozoic;
these movements, together with weathering processes, gave the Salair its
present relief.
The outstanding students of the area are Bolgov, Bulynikov, Derbikov,
Lobazin, Lopushinski, Speranski, Usov, and Iavorski.
The Kuznetsk coal basin attracted the attention of a great number of
geologists because the earliest Soviet investigations revealed that the volume
and quality of the local coals had no equal in the Soviet Union. For this
reason detailed maps for a number of mining localities appeared simultaneously
with the first general geological map of the region. Butov’s and Iavorski’s
over-all reports on the area appeared in 1927, Fomich’s over-all report
appeared in 1940, and 1941 saw the appearance of the Kuznetsk Basin Volume
of the Geology of the U.S.S.R. in which a number of geologists contributed
to a detailed analysis of the area.
The basin separates the Salair Ranges from the Alatau; the Shorian Upland
forms a lower southern margin of the basin. Intensely deformed Cambrian,
Ordovician, Silurian, Devonian, and lower Carboniferous formations outdrop

EA-I. Obruchev: Geology of Siberia

outcrop along the eastern margin of the basin, while slightly disturbed
Devonian and lower Carboniferous formations are found to the south and the
northwest. The coal deposits occupy the interior of the basin, and represent
the middle and upper Carboniferous, lower and upper Permian, Triassic, and
Jurassic formations. The degree of deformation of the strata decreases from
the margins of the basin inward. Porphyry and disbase intrusions are found
in the lower Paleozoic rocks along the eastern margins of the basin, while
basalt sills are intercalated in the Triassic and Jurassic rocks, on both
sides of the Tom River, in the mountains of the so-called “melaphyr horsehoe.”
Soviet geologists have worked out the detailed straitgraphy of the area.
Abundant fossil faunas and floras fix the age of the main coal beds as
Carboniferous and Permian, and establish the presence of Triassic and Jurassic
sequences that contain coal beds, contrary to the older impression that all the
coal deposits are of Permian age.
The structure of the basin has been formed by repeated pressure from the
Kusnetsk Alatau on the east and the Salair on the southwest. The Carboniferous,
Permian, and Triassic beds are conformable. The first regional folding of the
basin is ascribed to the early Cimmerian Kimmeridgian epoch of folding since the Jurassic
beds lie with mild angular unconformity upon the Triassic. The Jurassic and
earlier beds have been more intensely deformed by a later orogenic movement
that was accompanied by outpourings of basalts. It has been assigned tenta–
tively to a late Cimmerian Kimmeridgian orogenic epoch. Overthrusting is quite common
along the margins of the basin, but it diminishes toward the central areas.
It seems that the region occupied by the Kuznetsk Basin was a quiescent
syncline in early Carboniferous time, after intense Caledonian and early
Variscan folding. The thickness of the sediments and the large number of

EA-I. Obruchev: Geology in of Siberia

coal beds indicate that slow, spasmodic sinking was the only tectonic move–
ment up to the end of Triassic time. Longitudinal faults in the Kuznetsk
Alatau and the Salair determined the boundaries of the syncline and facili–
tated the downsinking. Finally, post-Jurassic block faulting in both ranges
deformed the sediments once more.
Among the many geologists who have worked in the Kuznetsk Basin, the
most significant contributions were made by Adler, Butov, Dorofesv, Ergolsk i a ia,
Kumpan, Neiburg, Usov, Fomichev, and especially, Iavorski. The fossil faunas
were described by Pagozin, Khalfin, Chernyshev, and Ianishevaki; the fossil
floras were described by Zalesski, Neiburg, Rad i chenk i o , and Khakhlov.
The Altai constitutes the southern half of the Altai-Saian region. The
southwestern portions of the Altai were known rather thoroughly before the
Revolution, inasmuch as mining operations had been conducted there since the
seventeenth century; the rest of the area was known only from the occasional
writings of travelers. The mining region, because of its economic importance,
was the object of intensive study by Soviet geologists. Detailed reports
about almost every part of the area exist, but only a few of these have been
published. The Altai Mountains have been investigated less thoroughly than
any other section, but the discovery of a variety of economic deposits valuable ores will
necessitate exhaustive studies there as well.
The presence of intensively metamorphosed pre-Cambrian rocks that include
small bodies of rock which may be Archean in age has been established; for the
most part, however, the pre-Cambrian rocks are Proterozoic and include
several thick patches of tillites, that is, metamorphosed boulder clays that
point to very ancient glaciations. Considerable thicknesses of Cambrian marbles
and fossil-bearing shale are present, but these are overshadowed by the thicknesses

EA-I. Obruchev: Geology in of Siberia

of Ordovician and Silurian fossil-bearing shales and limestone roofs.
Smaller thicknesses of Devonian terrigenous marls and red sandstones lie
unconformably upon the pre-Devonian sequence of rocks. In the valleys of
the Bia and Chuia rivers, to the northward, narrow, squeezed-in bands of
lower Carboniferous and Permian coal-bearing formations are found. Patches
of coal-bearing rocks of Tertiary age are found along the Chuia and Argut
rivers.
The geology of the Altai mining district is quite different; the
section’s pre-Cambrian and Cambrian rocks have not been examined yet, but
it has been established that the dominant local rocks are metamorphosed
Silurian, and marine Devonian, Carboniferous and lower Permian. Coal-bearing
rocks of Tertiary age have been found only on the Narym River.
A great variety of intrusive and extrusive rocks of various ages con–
stitutes an important component of the lithology of both sections of the
Altai. A number of granitold bodies are present; these frequently pass over
into porphyries. Basic rocks are present in smaller volume. The tectonic
structure of the Altai Mountains, also, is different from that of the mining
district; in the former section a Caledonian folding that strikes NW. -SE.,
but swings to a N E.-SW. Strike in the eastern part of the section dominates
the Paleozoic structure. The Devonian rocks are less intensely deformed, and
the Tertiary formations were disturbed by much more recent black movements.
All of the Paleozoic folds in the Altai mining district strike NW. -SE.;
these folds, however, are cut by two zones of crumpling that strike EW. -SE.,
and follow the faults at the margins of the Paleozoic geosyncline in which
great thicknesses of Devonian, Carboniferous, and early Permian sediments
accumulated, and were intruded by great bodies of Permian granite.

EA-I. Obruchev: Geology in of Siberia

V. A. Obruchev originally pointed out that the entire folded structure
of the Altai was completed in Paleozoic time. The region was almost base–
leveled in Mesozoic time. Cenozoic block faulting produced renewed uplift
in the region. This fact of block faulting accounts for the occurrence
of coal-bearing Permian formations as wedge-shaped outcrops among fault
lines, and for the upraised and somewhat folded condition of the local
Tertiary formations.
Quaternary and recent glaciations have been studied in the Altai in
considerable detail. One, or possibly two, glacial stages have been identi–
fied that antedated the Rise and Würm stages; the earliest of the regional
glaciations out into a different and less rugged terrain.
The most significant contributions to the store of information on the
geology of the Altai were made by Baklakov, Boldyrev, Bublichenko, Origprev,
Eliseev, Kotulskii, In. A. and V. A. Kuznetsov, Markhilevich, Nekhoroshev,
Padurov, the Tronovs, Churakov, and Shakhov. (The description of the Paleozoic
fauna is lagging far behind the geological field investigations.)
The Western Saian is the eastern continuation of the Altai Mountains.
Investigations have brought to light a wealth of new data. Red metamorphic
rocks of pre-Cambrian age seem to dominate the lithology of the region; smaller
sequences of Cambrian, Ordovician, Silurian, and Devonian rocks are also present.
Closer scrutiny, however, reveals that the regional Proterozoic component is
relatively minor, and that the greater part of the metamorphic and red rocks are
Lower and Middle Cambrian and Ordovician. In fact, it is the Cambrian and
Silurian formations that turn out to dominate the regional stratigraphy. Three
bands of iron-bearing quartzites represent the Silurian period. A Devonian
sequence, the Minusinsk series of the lower Carboniferous, and upper Carboniferous–
Permian coal-bearing formations are present in the northern foothills. The

EA-I. Obruchev: Geology in Russia of Siberia

supposed Triassic marine formations along the Us River constitutes a highly
problematical case, inasmuch as they were first dated on the basis of a poorly
preserved fossil fauna, and the dating was never verified. The intrusive
bodies found in the region are of Caledonian age, and possible pre-Cambrian.
A belt of Salair (Upper Cambrian) serpentines constitutes an ultrabasic
component of the regional lithology. The local extrusives are said to be
mainly Silurian. An examination of the local Quaternary formations indicates
two glaciations.
The tectonics of the Western Saian are as follows: The Variscan orogeny
compressed and overturned Cambrian and Ordovician folds that had been thrown
up in the course of Caledonian movements. These overturned folds were thrust
for great distances over upper Paleozoic rocks along the edge of the Minusinsk
Basin. Like the Altai Mountains, the Mesozoic and Cenozoic orogeny in the
area consisted of block faulting; these movements give the region its present
rugged relief.
The greater part of the material on the geology of the Western Saian
has been collected by Bazhenov.
The Minusinsk Depression is bounded on the west by the Kuznetsk Alatau,
on the south and east by the Western Saian, and on the north by the Eastern
Saian and the Solgon R r anges. The presence of copper, iron, gold, and asbestos
deposits attracted the attention of pre-Revolutionary geologists to the
region. Soviet geologists have continued the study of these deposits, dis–
closed the existence of now economic other deposits, and indicated the possible
presence of oil pools and salt. Maps have been issued and a great deal of
information collected, but several important problem still remain unsolved.
Two ranges that trend ENE. -WSW. divide the Depression into three basins.
Pre-Cambrian and lower Paleozoic rocks outcrop in the ranges; middle and upper
Paleozoic rocks occupy the basins. The Proterozoic period is represented by
limestones, graywackes, and siliceous slates; the sediments are intruded by

EA-I. Obruchev: Geology in Russia of Siberia

granites, gabbros, and porphyries. (A number of investigators regard this
sequence as Cambrian.) The limestones carry algae and erratics that were
presumably dropped from icebergs during a glacial epoch. The local Middle
and Upper Cambrian limestones contain algae and a fossil fauna, and are
intruded by diabases and porphyries. A series of tuffs and porphyries is
tentatively dated as Silurian. The sea retreated from the area in Silurian
time, but returned for a short time in the Devonian. The Lower Devonian rocks
are red plant-bearing sediments and effusive; the Middle Devonian sequence
begins with plant-bearing oil shales, while limestones with a marine fauna
constitute its upper portion; the Upper Devonian rocks are red terrigenous
sediments with fossil r f ish remains and plants. The Minusinsk series, which
some writers regard as lower Carboniferous and others as Upper Devonian
(on the basis of the fossil plants present), overlies the major Devonian
sequence. The Minusinsk series, in its turn, is overlain by a coal-bearing
series the age of which is still in doubt (upper Carboniferous or lower
Permian). Coal-bearing Jurassic rocks are found in the northernmost basin.
Tertiary deposits are minor. The Quaternary period is represented by sands
and loosses that contain plant remains and human artifacts.
It is doubtful whether Proterozoic folding movements took place in this
region as there does not seem to be a regional break between Proterozoic and
Cambrian sediments. The Caledonian folds have clearly geosynclinals character
and are contemporaneous with adamellitic and basic intrusions. Variscan
movements produced en e é chelon fold and domes in the basins of deposition
where Devonian, Carboniferous, and Permian sediments had accumulated. The
major faults at the margins of the depressions (occasionally associated with
thrusts and extrusives) had their origin in Caledonian movements, but are

EA-I. Obruchev: Geology in Russia of Siberia

largely the products of Variscan orogeny. The Jurassic beds in the northern–
most basin were deformed during a later orogeny.
The chief contributors to the geological literature of the Minusinsk
Depression are Bulynikov, Vologdin, Domarev, G. A. Ivanov, Krubetov, Churakov,
Shamanski and Edelshtein. Gromov’s and Sosnovakii’s studies of the region’s
Quaternary formations are noteworthy.
The Siberian Platform is bounded by the Eastern Saian on the south, by
the Yenisei Ridge on the west, and by the Taimyr Peninsula on the north.
Formerly, adequate data were available only on sections that lie in the
southern quarter of the Platform along the Trans-Siberian Railroad, in the
Yenisei gold mining district, along the Lena River, and in parts of the Viliui
River basin. The rest of the area was known only from the reports of occasional
field parties, and some of them very old. Recent investigations were carried
out in the coal fields of the Irkutsk, Kan, and Tunguska basins, the
Angara-Ilim iron district, the Norilsk pyrite deposits, the Viliui and Gulf
of Khatanga rock-salt deposits, and the Yenisei gold fields. The wartime
discovery of oil-trap structures in the Anabar Massif, the Viliui Basin, and
the Severnaia Zemlia Islands attracted a number of geologists to these areas.
Thus, virtually the entire Platform has been investigated, and even the Eastern
Saian, long a blank spot upon the map, has seen the day of its geologic mapping.
The pre-Cambrian foundations of the Platform outcrop, at the margins, in
the Yenisei Mountains Ridge , the Eastern Saian, the Cis-Baikal Cisbaikal R r anges, and the
Anabar Massif. The last-named massif, incidentally, was discovered by the
Baklund-Tolmachev expediton of 1905-1907, but is was not described geologically
until recently.
It is made up of Archean charnockite gneiss, granulites, and amphibolites.
These metamorphic rocks have been intruded by granite bodies and associated

EA-I. Obruchev: Geology in Russian of Siberia

offshoot veins, and basic dikes. Archean and Proterozoic rocks also outcrop
in the marginal areas which we shall discuss presently, and there is no
reason to doubt that they underlie the entire Platform. Cambrian, Ordovician,
and Silurian rock lie unconformably upon the pre-Paleozoic complex. They
have been studied by geologists in various degrees of detail. Lower, Middle,
and Upper Cambrian formations have been found on the Platform; the Middle
Cambrian limestones dominate the stratigraphic sequence of the Cambrian.
Calcareous and red-colored Ordovician and Silurian formations follow, the
latter indicating a withdrawal of the sea in the northern portion of the
Platform. This conclusion is supported by the fact that the Devonian forma–
tions in the Bakhta, lower Tungueka, and Kureika River valleys, near the
Yenisei River are colored red also. A Givetian (late Middle Devonian) marine
sequence is also found in the Bakhta Valley, however, and Frasnian (Upper
Devonian) limestones that carry corals and brachiopods are found in the Kheta
River basin. The mid-Devonian marine transgression does not appear to have
penetrated very far to the south. Fossil-bearing lower Carboniferous
(Tournaisian) marine strata are found along the Kureika and Tunguska rivers.
The sea retreated a great distance to the north in lower Carboniferous times,
and land conditions prevailed on the Platform from Visean through Liassic time.
The terrigenous upper Carboniferous and Permian Tunguska series lies
uncomformably upon early and mid-Paleozoic formations. It extends southward
along the Angara River, and almost reaches the Eastern Saian in the Kan River
basin. A study of the Tunguska series was not undertaken until recently, when
it was separated into the productive, the r t uff, and the lava-tuff divisions.
These investigations also revealed data on the fossil flora, the coal and
graphite deposits, and the olivine-diabase trap intrusions and extrusions.

EA-I. Obruchev: Geology in Russia of Siberia

The major area occupied by the Tunguska series has been termed the Tunguska
Basin and contains vast coal and graphite deposits. It extends eastward
into the Viliui River basin, as far as the Chona Rive.
Jurassic beds lie upon Paleozoic in the eastern portions of the Viliui
River basin; these were identified by Rzhonenitskii before the Revolution,
but have been studied in detail recently by geologists. The Lower Jurassic
formations are fresh-water sediments, the Middle Jurassic formations are
marine (ingression by seas from the north), and the Upper Jurassic formations
are terrigenous and coal-bearing. These rocks extend to the southern Lena
Valley, where studies of the coal deposits have been made between Kangalas
and Bulun. Farther north along the arctic littoral, Lower, Middle, and Upper
Triassic outcrops have been studied in the lower Olen s e k River valley, east
of the Gulf of Khatanga. Rhaetic-Liassic deposits that carry a fossil flora
are overlain by a later Jurassic marine sequence which, in its turn, is
overlain by coal-bearing Cretaceous sediments. This sequence is found farther
west, in the Khatanga Depression. Marine Devonian formations that overlie
early Paleozoic sequences are found to underlie Mesozoic strata at Solianaia
Sopka. This area contains deposits of rock salt , and pools of oil trapped natural gas, and oil.
against e S alt domes are numerous.
A Jurassic terrigenous sequence that contains deposits of coal and jet
lies directly upon early Paleozoic formations in the southern half of the
Platform (in the so-called Irkutsk Amphitheater). This sequence was studied
in the Irkutsk and Kan River basins (the Tunguska series outcrops at the margins
of the latter section), as well as in the less extensive Khakherei Basin
farther north, where oil shales and coals are found. Tertiary terrigenous
deposits are rare on the Siberian Platform. The deposits at of Quaternary age

EA-I. Obruchev: Geology in Russia of Siberia

found in the southern sections of the platform have been studied in much
greater detail, because of the presence of building materials there. Two
glacial stages have been identified in the northern part of the Platform
(the Tunguska Basin), and three glacial stages, plus two interglacial
marine transgressions from the north have been identified in its northeastern
sections.
Except for the extrusive rocks in the pre-Cambrian complex in the Anaber
Massif, traps are the only rocks of this type on the Platform. The main
concentration of traps is in the Tunguska Basin, but they are also found
in the Viliui River basin, to the east, and in the Irkutsk and Kan River
basins, to the south. The main outpourings of molten lavas occurred in
Permian time, but bursts of igneous activity occurred in Mesozoic, and possibly
even Tertiary time. Attention may be called to the A a lkali gabbro intrusions
along the Kheta River which are composed of ijolites and melteigites, and
associated extrusives chiefly augi i tic, melilitic, and limburgitic basalts;
the age of these igneous rocks is probably late Mesozoic.
Tectonically, the Siberian Platform is a great area of undisturbed
Paleozoic rocks that are deformed only at the Yenissi, Eastern Saian, and
Cis-Baikal Cisbaikal margins, where the strike of the folding parallels the strike
of the pre-Cambrian outcrops. The Cambrian rocks are slightly raised at
the margins of the Anabar Massif. The structure of the interior of the
Platform consists of extremely gentle folds in the Paleozoic rocks; rarely
does one see such gently rolling structure. Movements in the basement complex,
however, have generated shallow basins in the Viliui, Yenisei, and Saian sections
Both the Tunguska series and the Jurassic strata are folded in the Viliui
Basin, and at some points in the Irkutsk Basin. The main folding on the

EA-I. Obruchev: Geology in Russian of Siberia

Platform was of Caledonian date, though the Variscan Revolution produced
folding and faulting in the Tunguska Basin; the traps poured out along the
faults produced at that time. The Mesozoic era was a time of regional
oscillations that brought in Jurassic seas from the north and formed lakes
in the south; some weak folding also resulted. Oscillation continued into
Tertiary time.
The contributions of the following geologists stand out among the
many studies conducted in the area: A. I. Gusev, A. A. Grigorev,
Zhemchughnikov, Zegebart, Korovin, Levinson-Lessing, Maslov, Moor, S. Obruchev,
Otten, V. Sobolev, Tebenkov, Frishenfeld, and Iarahemeki.
The Yenisei Mountain Ridge north of the Angara River had been investigated
in considerable detail previously; the southern third of the mountain system
(south of the Angara) was known only roughly, however. Soviet research
concerned itself with the entire mountain system. A great Proterozoic
sequence that consists of series of metamorphosed slates, quartzites, and
limestones, topped by tillite, has been established here. Archean gneisses
and schists dominate the lithology south of the Angara River. These rocks
outcrop at some localities north of the Angara also; in any event, they are
close to the surface here. Local sequence of Lower Cambrian red sediments,
conglomerates, and sandstones are found, and Cambrian, Ordovician, and
Silurian deposits outcrop along the flanks of the mountains. The Archean
and Proterozoic rocks are intruded by granite bodies and associated veins.
Islands of coal-bearing Jurassic rocks are found in the central third of the
mountain system. Evidence of weak glaciations is found in the north.
Proterozoic folds strike NW. -SE. and cut the Yenisei River at an acute
angle. Caledonian folds of Cambrian, Ordovician, and Silurian strata are

EA-I. Obruchev: Geology in Russia of Siberia

pressed against both sides of the mountain system and faulted on a major
scale.
Gornostaev, In. Kuznetsov, I. G. Nikolaev, S. Obruchev, and Shchukin
are probably the leading students of the era.
The Taimyr Peninsula is separated from the Siberian Platform by the
Khatanga-Yenisei Depression. The area was hardly known before the Revolution,
and the adjacent Severnaia Zemlia Archipelago had just been opened. Outcrops
of pre-Cambrian granites, gneisses, mica schists, phyllites, and cherts are
found along the arctic coasts. Farther south these metamorphics are replaced
by outcrops of Ordovician and Silurian formations and rocks of the Tunguska
series with intruded traps. This complex constitutes the Byranga Plateau.
The Piasina River basin, to the west, is made up almost entirely of coal-bearing
formations of Tunguska age; marine deposits of Cretaceous age are also found
along the Yenisei River in this area. Upper Devonian (Fraenian) and lower
Carboniferous formations outcrop in the Efremov a s k uplift section; the basal
Tunguska beds are marine here. Lower Cambrian conglomerates cover the
Proterozoic metamorphosed slates on the Cheliuskin Peninsula, while all
three divisions of the Cambrian period are represented in the Severnaia Zemlia
Archipelago. The Quaternary period is represented by the moraines of two
glacial advances and the sediment laid down during one interglacial marine
transgression from the north.
There is considerable disagreement about the tectonics of the Taimyr
Peninsula. Early investigators in the area thought that a great thrust
movement had moved a mass of crystalline rocks over an Ordovician-Silurian
terrain, and had thrust the overridden Ordovician-Silurian rocks over a
Tunguska series terrain. The fault system was supposed to strike ENE.-WSW.
Subsequent investigations, however, have shown that the Caledonian folds were

EA-I. Obruchev: Geology in Russia of Siberia

overturned to the south, and that the regional fault system is characterized
by smaller displacements and is of Variscan origin. The folds swing to a
NE.-SW. and N.-S. strike on the Cheliuskin Peninsula, and assume a NNE.-SSW.
and NW.-SE. strike in the Severnaia Zemlia Archipelago; thrust faulting
complicates the structure in the latter section. The main orogeny in these
areas is also Caledonian and was accompanied by the intrusion of granite
bodies; the Variscan movements were accompanied by intrusion and extrusion
of trap. Mesozoic and Cenozoic movements were oscillatory.
Aller, Anikeev, Baklund, Liutkevich, Mutafi, Smirnov, and Urvantaev
have made significant contributions to the study of the geology of the Taimyr
Peninsula.
The Eastern Saian was as little known as the Taimyr Peninsula. Investi–
gation of the area was undertaken on a large scale in the middle 1930’s;
geological maps published in 1934 still contained large blank areas. The
now data indicate that Archean gneisses and amphibolites dominate the lithology
of the region. Proterozoic phyllites, sandstones, and limestones are second
in importance; these have been grouped into three series. The aggregate
thickness of the Proterozoic rocks is twenty kilometers (66,000 feet).
Cambrian shales, phyllites, sandstones, and limestones with subordinate
tuff and lava beds are present, in which an early and Middle Cambrian fossil
fauna has been found. The uppermost strata of this sequence may be Ordovician,
however. The volcanic rocks are generally taken to be Silurian-Devonian.
Marine conditions terminated in the Western Saian in Cambrian, or at the
latest, in Ordovician time. The Devonian period is represented by terrigenous
red sandstones and conglomerates of small thickness and lateral extent. At
two localities plant-bearing Jurassic lake deposits rest directly upon an eroded

EA-I. Obruchev: Geology in Russia of Siberia

pre-Cambrian surface. The Tertiary period is represented by conglomerates
that contain argillite lenses with Miocene plant remains. Those are over–
lain by a Quaternary basalt-moraine-basalt sequence.
The tectonic structure of the Eastern Saian is the product of Archean
and Proterozoic orogenic cycles; these included acidic and basic intrusions
and extrusions. There was no Caledonian geosyncline in the southwest, and
the northeastern portion of the region was part of an uplifted plateau. The
pre-Cambrian folds strike NW. -SE. whereas the Caledonian folds to the west
strike N W E .-SW. In Devonian time, land bridges that connected the entire
Saian to the Siberian Platform existed. Subsequently, the only tectonic
movements that occurred in the area were faulting, monoclonal flexuring, and
stage-by-stage regional uplift. The present relief of the region was determined
by basalt flows that filled the valleys in Quaternary time. Subsequent
studies have shown that previously inferred thrusts do not exist in the
region.
Bazhonov and Vologdin have done valuable work at the western end of the
mountain system; Konoplev, Molchanov, S. Obruchev, and N. Scbolev made the
most significant contributions to the geology of the greater portion of the
system, and S. Obruchev, after a three-year study, synthesized and interpreted
the tectonic and stratigraphic data of the region.
The Baikal Shield (the Ancient Roof of Asia), the Alden Shield, the
Stanovoi Mountains, and the Eastern Trans -B b aikal . Some parts of this region
were thoroughly known before the Revolution, other parts were known incompletely,
and still others were altogether unknown. The southern half of the Trans -B b aikal
was studied by a great number of field parties in connection with the construc–
tion of the Trans-Siberian Railroad; the northern half was less intensively

EA-I. Obruchev: Geology in Russia of Siberia

studied. A map (1 :4 2,000) of the Lena gold mining district and the Bodaibo
and Vacha River basins was based on the data gathered by a particularly
large number of field parties. The greater part of the area was not well
known at all, however, and the entire Aldan River basin, the Stanovoi
Mountains, and the area east of the Vitim River were known only from the
reports of occasional travelers. Local areas in the northern, central, and
southern Cis -B b aikal had been thoroughly studied, but only fragmentary inform–
tion was available about the rest of the area, as well as about the western
Khamar-Daban Mountains between the headwatersof the Dzhida River and the
Mongolian border.
Considerable advanced have been made in the geological study of the area
but these recent studies have not been uniformly intensive and have not
covered the entire region. The southern half of the eastern Trans -B b aikal and
various portions of the western Trans -B b aikal, the Cis -B b aikal, the Lena section,
and the Aldan Plateau have been thoroughly investigated; the other sections
of the region less thoroughly. If one judges by available literature, our
knowled ge of other parts of this vast region has not advanced beyond the
pre-Revolutionary scope of information. Unfortunately the reports of many
field parties have never been published; these probably contain much supple–
mentary material. The fact that publication lags considerably behind field
research limits our knowledge and hampers geologists. This lag, incidentally,
is not peculiar to the area under discussion but applies to all Siberian
geological literature; the delay is worst of all, however, in the case of
the eastern and northeastern areas.
The various sections are discussed separately, from west to east.
The Cis -B b aikal has been most thoroughly studied in the valleys of the

EA-I. Obruchev: Geology of Russia of Siberia

Buguldeika, Anga, and Sarma rivers, in the Lena Valley, and in the vicinity of
Cape Elckhin. The presence of Archean, Proterozoic, and Lower Cambrian forma–
tions has been established here. The Archean rocks have been grouped into
three divisions as have the Proterozoic; the Lower Cambrian formations, on
the other hand, have been divided into two units. The upper Proterozoic
rocks, which have been further grouped into the Colousten, the Uluntuisk, and
the Kachergat series, lie unconformably upon lower and middle Proterozoic
rocks. The g G olousten, Uluntuisk, and Kachergat series are not Cambrian, as
had been thought previously. The Cambrian sequence consists of the Motsk
conglomerates and the Ushakov series; it lies unconformably upon the Proterozoic
rocks. The region’s pre-Cambrian intrusions have been studied. Middle Cambrian
limestones and Upper Cambrian red sediments that merge upward into Ordovician
formations are found in the mountains in the western part of the section.
An early Quaternary river system that drained westward, rather than into
Lake Baikal, has been discovered; the reversal of drainage, of course, indi–
cates recent downsinking of the lake. Two glaciations have been identified
in the Primorskii Mountains, to the north.
The Archean and early Proterozoic folds in this section strike ENE.-WSW.,
that is, across the strike of the Lake Baikal structural depression. The folds
of upper Proterozoic age, on the other hand, strike NW-SE., while the Cambrian
folds strike again NE.-SW. and are overturned to the northwest. Geologists
still disagree as to whether the Cambrian folds constitute a marginal zone of
rocks that were squeezed against the Baikal Shield from the direction of the
Siberian Platform (Suess), or whether the Caledonian orogeny also involved the
Proterozoic rocks. The question whether the Archean rocks were thrust over
Jurassic formations in the Angara headwaters region by thrust faulting, or by

EA-I. Obruchev: Geology of Russia Siberia

reverse faulting, is also in dispute.
Pavlovski , Tsvetkov, and, in part, Katnshenok made the most significant
contributions on the geology of the central section of the region, Arsenev
and Maslov on the northern section, and Ge rv vr ussvich, Dumitreshko, and Kolenko
on the southern section.
The Baikal Upland has not been studied very thoroughly. Investigations
have established Archean rocks and a thick Proterozoic sequence that has
been grouped into several divisions. (These Proterozoic formations border
upon an area of Lower and Middle Cambrian outcrops.) The contact between
Proterozoic and Cambrian rocks has not been exactly determined and is
currently the subject of dispute (Ditmar, Dombrovski ) .
An area of old mica deposits along the lower course of the Mama River
has been studied thoroughly. Pegmatite dikes out crystalline limestones
and schists in a great syncline in a granite terrain (Markov, Misharev).
Much of the area between the Mama and Angara rivers remains unexplored.
Dumitrashko, however, has made geomorphological studies in the vicinity of
the Angara River. He has also collected new data about the Archean, Quaternary,
and late glacial deposits in the area.
The Lena gold district has seen a renewal of geological investigation
only recently, be means of field parties sent out by the Nigrizoloto and
Zolotorazvedka Gold Prospecting Agency. The first studies of the presumably
Proterozoic rocks in the valleys of the Bodaibo, upper Vacha, Nygra, and
Kadal rivers have led to a grouping of the rocks into four division. An
unconformity separates the second divisions from the third, and an as yet
unidentified fossil fauna has been found in the lowest division. Two ancient
erosion surfaces and several Quaternary formations have also been identified.

EA-I. Obruchev: Geology of Russia Siberia

Geologists tended to deny regional glaciations at first, but new data
indicate that glaciations has occurred. Zolotorazvedka field parties have
identified the morainal deposits of two glaciations of uncertain age in the
northern portions of the Zhuia River basin. Field parties of the Geological
Scientific Research and Development Institute (gold section) have divided
the Middle, and especially the Lower, Cambrian sequence into a number of
units along the lower courses of the Vitim and Bolshoi Patom rivers at the
borders of the Starostin district. Klevenskii, who worked along the Mal y i
Patom and Molvo rivers farther east, proved the existence of a thick Lower
Cambrian sequence; the sequence includes cong l omerates that carry granite and
gneiss fragments. Klevenski has also described a thin sequence of Middle
Cambrian limestones, and a great thickness of Upper Cambrian redbeds. These
findings are confirmed by Areenev’s, along the lower Olekma, farther east,
where the thickness of the Lower Cambrian sequence is 800 meters and that of
the Middle Cambrian sequence 75 meters.
Gerasimov has described the granites of the peak between the Ugakhan and
Nygra rivers on the basis of old data, and analysed their relation to the local
placer gold deposits. He assigns an early Cambrian date to the granites.
As regards the tectonics of the area, the latest investigations have
shown that the metamorphic rocks in the southern portion had been subject to
intense and complicated folding and that the Cambrian formations on the eastern
and southern margins are also strongly folded.
The western Trans -B b aikal has been described quite thoroughly in a great
number of hitherto unpublished reports. This is particularly true of the
Ba t r guzin section. We note, however, the publication of Eskola’s work on the
Sviatoi Nos [: ] and the upper B o a rguzin River valley; this treatment is

EA-I. Obruchev: Geology of Russia Siberia

based upon the Finnish geologist’s pre-Revolutionary observations, and
describes and interprets the Archean of both areas and the Proterozoic
rocks of the Barguzin Valley. Meister, Polovinkina, and Svitalskii have
described the geology of the northern Mui Mountains and the Vitim Plateau;
these geologists, like Eskola, based their treatment upon old data. Carusevich
and Zaklinskaia gathered new data on the geochemistry of the Archean rocks
in the Turka River basin. Pavlovski described the Archean, Proterozoic and
Cambrian tectonics, and the plentiful evidence of glaciations in the central
Vitim Upland. Arsenev investigated the central portions of the Vitim Valley;
he presented data on the tectonics, effects of glaciations, the upper Proterozoic
and Jurassic stratigraphic sequences, the granite intrusions, and the pre–
Cretaceous and Quaternary basalts.
Shatski has found a high-angle reverse fault that moved pre-Cambrian
over folded Jurassic rocks at the Selenga headwaters; he correlated it with
reverse faulting at the mouth of the Angara River. Tetiaev and Vasilevskii
studied the vicinity of the Pitatelevskii Springs. Tetiaev led a field party
into the neighboring Khamar-Daban and upper Udinsk region, where they mapped
the outcrops and the structure of the metamorphic, late Paleozoic and Mesozoic
formations, and established a post-Jurassic age of most of the granite intrusions.
Florensov and Larin investigated the coal series at Lake Gusin and grouped
the terrigenous strata into Upper Jurassic, Lower Cretaceous, and Tertiary
sequences. The Jurassic folds strike N W E -SW. here and Archean rocks are
thrust over Jurassic in the Monostoi Mountains. Arsenev investigated the
coal-bearing Tertiary series on the southeastern shores of Lake Baikal;
later, Riabukhin studied the sequence in connection with a local oil-prospecting
program. Palibin described the local Tertiary flora.

EA-I. Obruchev: Geology of Russia Siberia

A number of geologists — Garusevich, Korzhenskii, Pilipenko, and
Smirnov — have investigated the Sliudianka P p hlogopite deposits. The
local Archean rocks and the pegmatite dikes that cut them have been
described. Pilipenko found that the effects of glaciation in the Khemar–
Daban Mountains extend almost to the water level of Lake Baikal. Prokopenko
and the Lomakin Brothers crossed this range in its southern portion, between
the Irkut River basin plain and the headwaters of the Dzhida River. They mapped
the outcrops and make-up of the pre-Cambrian and lower Paleozoic sequences,
and noted the fundamental features of the basalts that outcrop on the peaks
of the range.
In the Dzhida headwaters section, Naletov studies the pre-Cambrian rocks
(one sequence carries algae), archaeocyathid-bearing Cambrian formations, the
Mesozoic coal series, the Quaternary deposits, the Caledonian and Variscan
folds and intrusions, and the younger basalts. Shalsev investigated the
central Dzhida Valley and found the same pre-Cambrian and Cambrian sequences,
in addition to Jurassic terrigenous beds, six igneous intrusions of various
ages, and the tuffs of three volcanic cycles. Vereshchagin had analyzed the
stratigraphy and tectonics of the coal series. Bes e o va has described the
Cambrian tungsten deposits in the Dzhida River. Levitski , Misharin,
Smolianinov, Speit, and others have also described these deposits.
Farther east, the Balegin iron ore deposits were investigated by
Domrachev and Pavlov, and were found to be sedimentary. Preobrazhenski
and Purtov measured the potential output.
In the central Khilka River S s ection, Vereshchagin investigated the
metamorphic rocks, the uppermost Paleozoic conglomerate series, the Jurassic
coal series, the Tertiary formations, the intrusive and extrusive rocks,
the younger basalts, and tectonics.

EA-I. Obruchev: Geology of Russia Siberia

Arsenev encountered crystalline and metamorphic pre-Cambrian and lower
Palezoic rocks in the Tsagankhuntei Range, as well as great granitoid bodies
and an upper Paleozoic tuff-lava series that is cut by alkali granites and
syenites. The syenites go over into grudurite and selvsbergite at the
margins. Teschenite loccoliths lift the layers of a Lower Cretaceous coal
series at one locality. Necheeva described the alkaline intrusions.
Dengin investigated the central Chikoi River basin, and described the
local metamorphic rocks, granites, extrusives, tectonics, and the Gutai
molybdemm deposits. Voskresenskii investigated the gold deposits in the
Chikoi gold district (as did Malyshev and Staln e o v) and studied the morainal
and terraced terrain there. The Cutai mining district was investigated by
Tataev and Fersman, and Donskoi called attention to the fact that the fossil–
bearing local lower Carboniferous sequence rests unconformably upon meta–
morphic rocks.
The mineal springs and lakes of the western Trans -B b aikal have been
described by Butyrin, Gladtsin, Dengin, Nikolaev, Tolstikhin, Frank-Kementskii,
and others; Soanovskii described the local paleolithic artifacts.
The Aldan Plateau was known p o nly from the reconnaissance data that
Zverev gathered along the Maia and Aldan rivers, and from the older data
gathered by Middendorf and Meglitski. Recent research, however, has ampli–
fied our knowledge of the region considerably. In the extreme wester n portion
of the region , the Tommot gold mining district was described by Zverev
and later by Bakhvalov. The latter described the Archean basement complex,
and its intrusives, the Lower Cambrian marine sequence, the terrigenous
Jurassic sequence, the subsequent alkaline syenites intrusive and basic dikes,
the Archean folding, and the post-Jurassic faulting and block movements.

EA-I. Obruchev: Geology of Russia Siberia

Arsenev divided the Archean sequence along the Olemka River into three units.
Fastalovich and Petrovskii described two types of gold [] d eposits in the
L a e bedinsk mining district. Korzhenski crossed the plateau as far as the
T y i mpton River. He investigated the petrography of the Archean rocks and
the stratigraphy of the Cambrian and Jurassic sequences, classified the
metamorphic rocks according to depth, and reported several varieties of
cyanite and corundum.
The gold deposits in Archean rocks between the Aldan and T y i mpton rivers
were described by Serpukhov. Ivanov and Stoliar discovered and described
the Uchurochiulbin gold district. This involved the investigation of the
local Archean complex, the very thick Cambrian sequence with its cong l omerates
and fossil fauna, the basic igneous rocks, and the structure. In the subse–
quently discovered Allakhiun Allakh-Iun gold district, in the northern portion of
the plateau, Bilibin, Baikov, Dzevanovskii, Potebinia, Serpukhov, and others
described the Lower and Middle Cambrian, Ordovician, Silurian, Upper Devonian,
upper Carboniferous, Permian, and Triassic sequences; the various intrusions
and the local tectonic effects of the Caledonian, Variscan, and later orogeny;
the gold deposits and the local effects of glaciations. Postoev noted the
effect of the latest tectonic movements in his geomorphological analysis
of the section. Iakzhin described the plateau’s phlogopit s e deposits.
The Stanov i o Mountains border the Aldan Plateau on the south. To this
day our knowledge of the regional geology is fragmentary. Obruchev drew
the inference, from new data that the Stanovoi Mountains are entirely separate
and distinct from the Iablonovyi Range. The distinctions are orographic as
well as tectonic. Obruchev described the pre-Cambrian and its intrusion,
as well as the more recent extrusives and tectonics. Anert compiled the

EA-I. Obruchev: Geology of Russia Siberia

older materials on the Tuskan and Mulam river headwaters region, and
Korzhenaki i conducted a geological reconnaissance along an Amur-Yakutia
route, mapped the more recent intrusive, extrusives, and the tectonic
structures, and established the boundaries and litho lo gic character of the
pre-Cambrian, Paleozoic, and Jurassic sequences.
Florov described the Aian gold district; Vasilchenko described the
porphyries, tuffs, and sedimentary rocks of the Ulia River basin; and
Leontovich seven Cambrian formations (one fossil-bearing) in the central
Mai n a Valley, as well as the Cambrian gabbro-diabase dikes and sills, the
Devonian and Mesozoic formations, and the granitoids and porphyries along
the Sea of Okhotsk coast. Alekseichik investigated the stratigraphy,
tectonics, oil possibilities, and oil-shale reserves in the Aim River section.
Pavlovski i extended Obruchev’s idea that the Stanovoi Mountains are the
upper hinge of the young monoclinal flexure that affects the entire Baikal
s S hield as far southwest as the shores of Lake Baikal, and as far south as
the Mongolian border. Pavlovski i also called attention to the large number
of grabens (including the Lake Baikal graben) in the Trans -B b aikal region.
He also studied the times of origin for the grabens and their similarity
to the grabens of Africa, and suggested that the Baikal grabens are downthrown
blocks between twin sets of reverse faults rather than the downdropped blocks
of rifts, that is, they are the products of horst tectonics.
The eastern Trans -B b aikal was known, at first, only from engineering
reports on the Nerchinsk district; later on during the construction of the
Trnas-Siberian Railroad, Gerasimov and Gedroits made a reconnaissance of the
southern portion of the region, and Voznesonski i and Makerov of the northern,
More recent research has yielded a great deal of new material, some quite

EA-I. Obruchev: Geology of Russia Siberia

unexpected largely from the southern section. The northern portion of the
region — the Olekma headwaters and the Ingoda and shilka river valleys —
have been explored much less intensively.
Proceeding from m s outh to north, the following are the most significant
results of geological exploration in the region.
Immediately after the Revolution Zver [] ev, Krektar, Svitlovaki i , and
Smirnov studied and described the Nerchinak silver-lead-zinc deposits.
Artemev further described the lead deposits; Vardaniants, Doktorovich,
Crebnitski i , Sushchinski i , and Tetiaev described the tungsten and precious
stones deposits; and Arsenev and Makerov the local gold deposits. Obruchev
described the Ilinsk and Evgrafovsk gold deposits on the basis of data
gathered in 1912; Savalev described the latter.
Between 1925 and 1929 a number of field parties under Tetisev investi–
gated the eastern half of the area. These parties studied the fossil fauna,
the marine Devonian sedimentary rocks, the lower Carboniferous sedimentary
rocks (formerly regarded as Devonian), and the Permian, Upper and Lower
Triassic, Lower and Middle Jurassic, terrigenous Lower Cretaceous, and
Tertiary formations. These geologists dated the metamorphic rocks of the
section as Paleozoic (unfossiliferous). They also determined that the
tectonic development began with recurrent thrusting (“ [] t ectonic lamination”)
to the southeast. These inferences grew out of comparisons to the nappes of
the Alps and western Europe. A reevaluation of regional maps after 1929 showed
that these conclusions were wrong; high-angle reverse faulting rather than
nappe structure dominates the tectonic picture. These investigations also
revealed a smaller area of granite intrusion, the presence of scattered
Ordovician-Silurian outcrops, the possibility of pre-Cambrian outcrops, and

EA-I. Obruchev: Geology of Russia Siberia

the presence of complicated large-scale folds that strike N W E .-SW. associated
with a set of north-south folds of Variscan date or at least older than
Upper Jurassic. It is possible that Caledonian folds are present also. A
considerable portion of the granitic rocks is older than Upper Jurassic and
is, in fact, pre-Permian, that is, Variscan age. It has been confirmed
that the local neutral and alkaline extrusives are late Jurassic, and the
basalts are Tertiary and Quaternary. The upper Mesozoic and Tertiary tectonic
movements took the form of upward and downward block faulting that was asso–
ciated with volcanic activity, thrusting, and a gentle folding of Cretaceous
and Tertiary strata.
These later investigations were carried out by Atlasov, Luchitski i ,
Maksimov, Maslov, Pavlovski i , Rudnev, D. S. Sokolov, Khudiaev, Shchukin, and
others.
Artemev, Kreiter, Smirnov, and others continued their study of the local
silver, lead, zinc, tungsten, and tin deposits. A new tin district in the
Onon headwaters section has been repeatedly examined and described. Pavlov,
Pilipenko, and Lavrovich described the fluorite and gold deposits along the
Onon and Unda rivers. Various geologists have described the Chernovsk,
Khalbon, and Kharanor coal deposits. The ground water, mineral springs, and
hydrolaccoliths of the region were studied by Gladtsin, Dzens-Litovski i ,
Makorov, Silin-Bekoburin, and Tolstikhin; the salt lakes were investigated
by Pavlov; the fossil fauna by Kichigina, Krymgolts, Nekhorochev, Rukhin, and
Khudiaev; and the fossil flora by Khakhlov. Sheimsan has synthesized the data
on the structure of the eastern Trans -B b aikal, and has correlated it with the
structure of Mongolia.
Nenadkevich and Khrush o c hev studied the bismuth deposits along the Kara

EA-I. Obruchev: Geology of Russia Siberia

and Amazar rivers, in the northern half of the region. Gor oønostaev, Zemel,
Rikhin, Khakhlov, and others investigated the gold-bearing quartz and
tourmaline veins along the Kara River. The Darasunsk gold and polymetallic
deposits were also studied. Eight full reports on the geology of the
Bukachachinsk coal deposits are available. The Ushmunsk tungsten deposits
have also been described in detail. Efremov, Pavlovski i , and Sobolev have
gathered new data in the upper Olekma Valley.
The Amur Region and the Southern Maritime Provinces (Including Sakhalin) .
Before the Revolution, a small amount of data about those sections of this
region that lie along the Amur and Ussuri railway route was available, and
considerable data about the geology of the gold districts along the Zeia,
Selemdzha, and Amgun rivers. Incomplete data were also available about the
Uda River basin, the Ozornyi (Lake) section, the Sikhote-Alin Ranges, and
Sakhalin Island. The coal deposits of western Sakhalin and the small oil
deposits in the eastern part of the island had been studied.
Recent development of mining industries and the construction of the
Baikal-Amur Railway trunk line has advanced our knowledge of the geology
of the region immeasurably. The most thorough studies were made in the
Bureia River basin, the Mal y i Khingan Mountains, the southern portion of the
Sikhots-Alin, the southern portion of the Ussuri section, and Sakhalin Island.
In the northern sections of the region, however, the section from Zeia head–
waters to the mouth of the Amur remained virtually neglected. The great
energy with which the Far East Section of the Soviet Geological Survey
carried research forward, in this region, is worthy of attention; since this
organization’s headquarters have been moved from Vladivostok to Khabarovsk
(when the Geological Survey became the Geological Administration), its activities

EA-I. Obruchev: Geology of Russia Siberia

in the Far East have tapered off, and the publication of materials on the
region under consideration has ceased.
The Ka A mur section was subject to intensive geological investigation
because of the presence of gold, schoelite, and antimony deposits along
the Zeia River and in the Tukuringra Mountains. These deposits were studied
by Ar o sentev, Makerov, Popov, Preobrazhenski i , and
others. The tungsten and molybdenum deposits along the Selemdzha-Bureia
divide have been investigated by Artemev, Vitgeft, Volarovich, Golubin,
Mokin, and others. The iron-bearing quartzites of the Mal y i Khingan were
studied by Aleksandrov, Vitgeft, Danilovich, Dubrov, Pavlov, Sokolov, and
Tkalich. Jurassic and Tertiary coal deposits elsewhere in the section have
been examined to a lesser extent. The leading investigators of these deposits
have been Arsentev, Bochkovskaia, Bykov, Davydov, Konstantov, Matvcev,
Ponomarenko, Skorokhod, Kheraskov, and Shatski i .
Other economic deposits that have been investigated include the Oldoi
River platinums, the Bogucha m n River fluorites, and the Soiuznoe mineral springs,
as well as the effects of glaciation in the Tukuringra Mountains, and permafrost.
The geology of the Jewish Autonomous Province has been investigated (Abdulaev,
Krishtofovich, Bruk, and Shkorbatov), as have been the geology along the
Baikal-Amur trunk line and the region’s soils and swamps. A number of reports
on the petrography of the various sections have appeared (Afanasev, Bolshakov,
Dominikovski i , Lebedev, Polovinkin, Stron, and Suslov). Brauner, Voronets,
Riabinin, and Sokolov have described the fossil faunas of the region, and
Krishtofovich, Maslov, Prinada, and Shtempel the fossil floras.
These investigators ascertained age, structure, and genesis of previously
known and newly discovered economic deposits, and described the geology of the
region. The greater part of the regional terrain is found to consist of
Archean and Proterozoic rocks; a lesser part of Ordovician, Silurian, Devonian,

EA-I. Obruchev: Geology of Russia Siberia

and Lower Jurassic marine sequences, terrigenous Upper Jurassic and Cretaceous
and Tertiary formations. The pre-Cambrian and Paleozoic rocks contain many
intrusives, and the Jurassic sediments have also been invaded by young
granites; the latter are still the center of considerable controversy, however.
The strike and degree of deformation of pre-Cambrian, Paleozoic, and Mesozoic
folding have been clarified. The tectonics of the Malyi Khingan, in par–
ticular, have been clarified. Here the pre-Cambrian folds strike N.-S. and
the Mesozoic folds strike NE.-SW.; the latter, however, are influenced by
the former. Pre-Devonian, pre-Jurassic, Upper Jurassic or Lower Cretaceous,
and pre-Tertiary orogenic cycles have been identified, in addition to the
pre-Cambrian. The Tertiary folding was gentle.
The Southern Maritime Provinces attracted geologists’ attention because
iron and coal deposits exist in the vicinity of Vladivostok and in the
Sikhote-Alin Mountains. The northern half of the region, along the Amur
and Amgun rivers, and the Ozernyi section between them, has been investigated
less thoroughly.
A considerable number of geologists have studied the Permian-to-Tertiary
coal deposits in the islands, peninsulas, and coastal areas around Vladivostok,
and along the lower Suchan River. The Suchan coal deposits are found at depth.
The Triassic, Jurassic, Cretaceous, and Tertiary rock sequences here have
been the subject of a great number of studies, both incidental and special;
the age of the rocks, of course, was determined paleontologically. The
Triassic and Jurassic periods were marked by marine transgressions and
volcanism.
Among the outstanding students of the region are Anert . , Vittenburg,
Elieshevich, Kozlov, A. I. Krishtofovich, Libus, Pavlov, M. Preobrazhenski i ,

EA-I. Obruchev: Geology of Russia Siberia

Prinada, Tkalich, and Shtempel.
To the north, in the Suifun section, Koslov, A. I. Krishtofovich,
Pentegov, Precorazhenski i , and Iavorski i investigated the Jurassic coal
basin and the iron deposits.
The southern portion of the Sikhote-Alin Mountains contain a number
of exploitable deposits in addition to the Suchan coal field. These include
the magnetite deposits of the Olginsk-Vladimirsk section, Tetiukhe Ppoly–
metallic deposits, and a number of points at which tin can be mined by
open-pit methods. Thus far, gold and oil prospecting has gone forward only
on the reconnssance level. The main stock of data on the area has been
gathered by Volarovich, Gregorev, Dervis, Danilovich, Ivantishin, Kozlov,
A. I. Preobrazhenski, Rusakov, Smirnov, and Skorokhod. Skorokhod and
Volarovich wrote a general report on the area.
The Khekhtayr Mountains south of Khabarovsk, along the lower Ussuri
River, were first studied by Leontovich, Prinada, and Pek. The Amur River
below Khabarovsk was studied by a field party that was sponsored by the
Soviet Academy of Science s and consisted of Danilovich, Kozlov, and Sokolov.
The field party found marine sediments of Triassic, Jurassic, and early
Cretaceous age, a Tertiary cola series, and both intrusives and extrusives.
Malioranski i explored the northern portion of the Sikhote-Alin between
Lake Kizi and the mouth of the Amur, and found that extrusive rocks dominate
the lithology. Alekseevski i and Polevoi investigated the iron deposits in
the basalt section around Nikol s a evsk, and Preobrazhenski i the gold placer
deposits along the Limura River. Kazanski i first explored the Ozernyi section,
in 1914, but his report did not appear until after the Revolution. Subsequently
Efremov and Pavlovski i studied the area and found great thicknesses of upper

EA-I. Obruchev: Geology of Russia Siberia

Paleozoic and Triassic sediments, evidence of recent oscillatory movements,
and extrusive basalts. Arsentev, followed by Preobrazbenski i and Seregin,
investigated the O C hlia-Orel lakes, mount Belaia, and Kol River gold deposits.
Mikhnovich investigated the Komsomolsk section, and found Middle and Upper
Triassic and Lower Cretaceous sediments, and Cretaceous granitoids and young
basalts. Bagurin found tungsten and tin deposits at Lake Udyl and along
the lower Amur.
The fossil fauna of the region was collected and identified by Vittenburg,
Voronets, Kiparisov, Kokkerel, Kruglov, Krymgolts, Martynov, and Riabinin;
the fossil flora was described by Zalesski i , Krasser, Krishtofovich, Maslov,
Palibin, Prinada, and Shtempel.
The study of the tectonics of the Sikhote-Alin Mountains has not advanced
very far. Generally speaking, however, the structure seems to be a pair of
major anticlines, the combined width of which exceeds that of the mountain
system. The anticlines strike N [] E .-SW., and carry large brachyanticlines.
The outcrops on the crests of these anticlines consist of early and late
Paleozoic rocks, while Mesozoic rocks form the limbs. Cretaceous rocks,
deformed less than their predecessors, occupy the s u y nclines and are overlain
by Tertiary rocks that are even less deformed. The tectonic results of several
orogenic movements are superimposed upon one another. The last powerful
disturbance took place in the Kimmerian Kimeridgian orogenic epoch and was accompanied
by granite intrusion. The molding of the geanticline was completed in the
Austrian epoch when high-angle reverse faulting and volcanic activity began
which continued for some time. The great thrust from the southeast postulated
by Tetiaev and a number of his colleagues does not exist.
Sakhalin Island was rather well known geologically before the Revolution,

EA-I. Obruchev: Geology of Russia Siberia

but more detailed studies of the island have been made since that time
especially in the coal and oil regions. An intensive study of well sections,
cross sections and paleontological data led to a detailed knowledge of the
marine, terrigeonous, and extrusive Cretaceous and Tertiary rocks that make
up most of Sakhalin. The coals and geology of the western shore have been
studied by Vitgeft, Volkovich, Gapeev, I latov, Krishtofovich, Polevoi, and
the Japanese geologists Yabe and Shimitsu. The petroleum deposits of the
western shore were investigated by Bunin, Krish ot to fovich, and Shcherbakov,
and the main pools, on the eastern shore by Abazov, Gedroits, Damperov,
Kobziashi, Kosygin, Mironov, Perfilev, Polevol, Tanasevich, Khomenko, and
others. The two interior mountain chains, which include Paleozoic rocks
and contain gold deposits, have been studied by Vitgeft, Eliscev, Krishtofovich,
and Khomenko; Smekhov, Khmolev, Khomenko, and Shakhov investigated the geology
of the Schmidt Peninsula.
The fossil fauna of the island was investigated by Argomakov, Voloshinov,
Gayaseka, Nagao, Chernyshev, Khomenko, and Isbe, and the fossils flora by
Krishtofovich and Poiakrov. Krishtofovich, Polevoi, Sokolov, and Tikhonovich
wrote a general treatment of the geology of the island.
According to Pleshakov’s recent study, Sakhalin Island is made up of
folded geosynclinals sediments of late Cretaceous and Tertiary age. Six
stages of the Alpine orogeny are discernable; the Kamchatkan disturbance,
between the Upper Cretaceous and the Tertiary; the Kurilean disturbance,
between the Oligocene and Miocene; the Amurian disturbance, between the
middle and late Miocene; the Tatarian disturbance, in the upper Pliocene;
and the Okhotsk disturbance, in Pleistocene time. The island has been sinking
since the latter half of the Pleistocene time. The folds are overturned to

EA-I. Obruchev: Geology of Russia Siberia

both east and west, and are associated with faults and thrusts.
The Northeastern Region includes the upper Verkh o i nsk ansk -Kolyma section,
the Chukotsk-Anadyr section, and the Kamchatka P eninsula. This was the
least known portion of Siberia. The only available data about the region
consisted of the reports of occasional travelers; some of these were very
old. After the Revolution the Northern Sea Route Administration whose ships —
the region’s only source of supplies — round these coasts, undertook geo–
logical investigations. The discovery of precious metals, coal, and petroleum
started a study of the entire area.
The Soviet Academy expeditions to Kamchatka and the founding of the
Volcanological Station there laid the foundations for the systematic study
of the only part of the Soviet Union where active volcanoes exist. Unfor–
tunately, the reports of the field parties that worked under the auspices
of the Kamchatka Trust, and the Daletroi (q.v.) organization that succeeded
it, have never been published.
The Upper Iana Verkhoiansk -Kolyma section include s the great vast Iana, Kolyme, and Indigirka
river basins. Before the Revolution parts of the region had been visited by
reconnaissance parties under Wrangel, Toll, Volosovich, Maidel, Tolmachev,
and Cherski i . Vast areas, however, remained unknown.
All of the mountain ranges which separate the river basins have been
studied since, and these investigations resulted in the discovery, by a party
under S. V. Obruchev, of a great mountain system between the Indigirka and
Kolyma river basins. This system, which was named the Cherski i Mountains
after the geologist who first crossed it at a point at which its extent and
elevation cannot be seen, consists of several ranges of rugged relief which
shelter small mountain glaciers. The basins of the section’s most important

EA-I. Obruchev: Geology of Russia Siberia

rivers were studied, as were several less important upland areas along the
arctic littoral, and several river divides along the Okhotsk littoral to
the south.
A considerable number of geologists have investigated the Verkhoiansk
Mountains recently. A. A. Grigorev laid the groundwork for these investiga–
tions when he crossed these mountains in their central portion. Thereafter
geologists turned their attention to the old silver- and lead-mining districts
in these mountains, and to the Orulgan and Kharsulakh Mountains farther north,
In the latest phase of the study of the area, geologists have ventured into
the mountains to the south of Grigorev’s route. The northwestern portion of
the area has been found to consist of a uniform series of Permian, Triassic,
and Jurassic sandstones. (One member of the local Permian sequence carries a
fossil flora.) Cambrian, Ordovician, Silurian, Devonian, and Carboniferous
formations outcrop beneath the Permian in the Kharaulakh Range; Lower Cretaceous
marine and terrigeonous Tertiary sequences overlie the Permian. Pre-Cambrian,
Cambrian, Ordovician, Silurian, Permian, and Triassic strata, and intrusives,
little represented in the northwest, outcrop in the southeastern part of the
region. On the whole, erosion has not reached the Mesozoic rocks in the
northwest.
Tectonically, the Kharaulakh Range consists of folds that have been
overturned and thrust to the west. Late Mesozoic tectonic movements have
masked the results of Caledonian and Variscan orogenics. The reasons for
the arcuate shape of the range are not yet understood.
The quite recent discovery of tin along the Adycha River has attracted
geologists to the great basin of the Iana River; geological investigations
have not progressed very far, however. The metals are genetically connected

EA-I. Obruchev: Geology of Russia Siberia

with Cretaceous granites that have out lower Permian, Upper Triassic, and
Jurassic sediments.
Little is known about the Tas-Khaiakhtakh Mountains, with their Cambrian,
Ordovician, Silurian, Devonian, upper Paleozoic, Triassic, and Jurassic marine
formations; its Tertiary and Quaternary sequences; and its periods of igneous
activity (the last igneous rocks were emplaced in Cretaceous times).
The relationships between the Cherski i Mountains and the Tas-Khaiakhtakh
are not clear as yet. The former system consists of nine or ten high ranges.
Though Paleozoic rocks outcrop at some points, Triassic and Jurassic forma–
tions cut by granites dominate the lithology of the mountain system. At
some points the Mesozoic sequence also includes Lower and Upper Cretaceous
terrigeonous formations. Folds that were thrown up in a Mesozoic synclinorium
that formed after the folding of the sediments in Paleozoic times constitute
the tectonic structure of the mountain system. These Mesozoic folds are
overturned to the north and south. Among the igneous rocks post-Silurian
granites and diorites, Upper Jurassic and Lower Cretaceous granites, and
Jurassic extrusives are found. Two quite granite intrusions brought
in rich deposits of gold and tin.
The Kolyma-Iukagir Platform, northeast of the Cherski i Mountains, served
as a central massif around which the Mesozoic geosynclines formed, and against
which the folds of the Mesozoic sediments were braced. The Platform itself,
however, was subject to fairly strong tectonic deformation. Pre-Cambrian,
Cambrian, Ordovician, Silurian, Devonian, and lower Carboniferous formations
are encountered; they seem to be geosynclinal deposits and are strongly deformed.
In passing from the Cherski i Mountains to the Kolyma-Iukagir Platform, one
notices that the Triassic formations lose thickness and turn red. The Jurassic

EA-I. Obruchev: Geology of Russia Siberia

sequence includes lavas, tuffs, and coal beds. The Mesozoic formations are
folded. Young liparites and teschenites are encountered.
The Kolyma-Okhotsk Divide, which was formerly considered to be a continu–
ation of the Stanovoi Mountains, has been found in its eastern portion to
consist of terrigeonous upper Permian formations, three divisions of a marine
Triassic sequence, Jurassic formations, and a Cretaceous sequence rich in
extrusives. Again, in the Okhota, Gusinka, Ulbei, and Kukhtui river valleys,
to the west, Triassic-to - Cretaceous formations are found to be accompanied by extru–
sions and granite intrusions. Tertiary sediments and extrusive liparites and
marekanites are found along the Okhotsk coast.
The chain of coastal plateaus that includes such ranges as the Sviatoi
Nos, the Alazeia, the Polous, and the Aniui is incompletely known. At central
points in these plateaus, Cambrian, Ordovician, Silurian, Carboniferous, and
Permian formations occur, but Triassic, Jurassic, Lower Cretaceous and, to a
lesser extent, Tertiary formations dominate the regional picture. The
products of volcanic activity that ended in Quaternary time (chiefly basalts)
are widespread. The strike of the folds appears to follow that of the folds
of the Kolyma Platform.
Only Bolshoi Liakhovski i Island, in the Novo-Sibirski i Archipelago, has
been studied with any considerable thoroughness recently; we must depend upon
old data for our knowledge of the rest of the archipelago. A Cambrian sequence
is known from Bennett Island, and the Kotelyni Island contains sedimentary
formations of Ordovician, Silurian, Devonian, Carboniferous, Triassic, Jurassic,
Tertiary, and Quaternary age, as well as Jurassic granites and Tertiary basalts.
Tectonically, the island in the southern portion of the archipelago belongs to
the Verkhoiansk folded complex. The Paleozoic strata on Bennett Island are

EA-I. Obruchev: Geology of Russia Siberia

not disturbed, and this had led some geologists to postulate a Great Arctic
Shield which, for the most part, is now submerged.
Recent investigations in this area have brought to light much information
on continental glaciations (two or three stages), stream sculpture and pene–
planation, permafrost, ground-ice volume, firnification, and soil geology.
Several geologists have already written general treatises of the section.
Twenty-two investigators have studied the fossil fauna, and four the fossil
flora.
Geologists who have participated in the study of the region in spite of
handicaps are Atlasov, Vak e a r, the Gusevs, Ermolaev, Lazurkin, Nikolaev,
S. Obruchev, Saks, Smirnov, Fedortsev, and Kheraskev. Kupletski i made the
petrographic analysis of specimens collected by various workers.
The Chukotka-Anadyr section constitutes the eastern third of arctic
Siberia. It had been poorly investigated before the Revolution. The discovery
of placer-gold deposits in Alaska at the turn of the century occasioned the
exploration of the coast of the Bering Sea by the Bogdanovich expedition.
R L ater the Polevoi expedition penetrated to the central portion of the Anadyr
River basin. The investigation of the region made great advances recently;
even so, we do not know the geology of the entire area yet. The latest data
seem to indicate that the section has three orographic divisions: ( 1 ) the
Chukotka Range in its northern portion; ( 2 ) the Anadyr Plateau in its central
portion; and ( 3 ) the Gydan and Anadyr ranges (a continuation of the O [] khotsk–
Koly nma Divide) in its southern portion. The Anadyr Depression and its minor
mountain ranges, and the Korisk Mountains to the south, are a continuation of
the Kamchatka Upland.
In the Chukotka Range there is a belt of pre-Cambrian marbles and crystalline

EA-I. Obruchev: Geology of Russia Siberia

rocks that extends from Koliuchinski Bay to the Bering Strait. In addition,
geologists have found fossil-bearing Silurian, Devonian, and Carboniferous
marine sediments, Permian phyllites, an upper Triassic sequence, and Jurassic
coal-bearing and lava-tuff sequences. The pre-Cambrian and Paleozoic rocks
strike WNW.-ESE., and are intensely deformed and intruded. The most important
tectonic feature of the range, however, is a set of folds of Kimeridgian
(Jurassic) date that also strikes WNW.-ESE. Post Jurassic gabbros, mepheline
syenite, granites, and acid extrusives enter into the composition of the Dezhnev
Range.
The Anadyr Plateaus is made up of Cenozoic lavas and tuffs. Evidence of
Quaternary volcanism is present.
The Gydan Range is the divide between the Omolon River (a tributary of
the Kolyma) and the Gizhiga. The country rock is pre-Cambrian and Paleozoic.
Intruded metamorphic rocks of Proterozoic-Paleozoic age (counterparts of the
basement-complex rocks in Alaska) outcrop in these mountains as well as on
the coasts of the Bering Strait; in the latter area, however, these rocks
are covered by extrusives. The lithology of the Anadyr Range, on the other
hand, is dominated by Jurassic, Cretaceous, and Tertiary marine formation,
intruded by a variety of acid and alkaline igneous bodies which were emplaced
by the various regional cycles of tectonic movement and igneous activity.
These injections of magma occurred in Kimeridgian, Austrian, Laramide, and
Oligocene time, and later. The same Mesozoic and Cenozoic sedimentary and
igneous sequences are found in the minor ranges of the Anadyr Basin.
The Korlak Mountains are, in the main, made up of sandstones, siliceous
shales, in part tuffaceous, and great thicknesses of Tertiary sandstone.
These sediments were folded in a Tertiary-Quaternary transitional orogeny.
Their structure is complicated by normal and reverse faulting, and their
strike is NE.-SW. Later tectonic movements have occurred in the area. Coal
deposits of Cretaceous and Tertiary age are found at the eastern end of the

EA-I. Obruchev: Geology in of Siberia

mountain system; gabbro, gabbrodiorite, and pyroxenites intrusive are wide–
spread in the area, as are porphyritic and a n desitic extrusives.
The geology of Wrangel Island was virtually unknown until quite recently.
Lately, however, the island was studied in connection with the work of a
Soviet Academy expedition which was sent out to collect mammoth remains. The
report of this expedition has not been published yet, but it is known that the
island is made up of upper Carboniferous and Upper Triassic rocks, the latter
of marine origin.
A number of workers have investigated past glaciations of the region, and
their effect upon the development of the terrace and permafrost. Data about
mineral springs and the peat deposits of the Anadyr tundra has also been
gathered. Geologists have collected a few fossil faunas and floras.
Soviet geologists who have gathered most of the information about the
section are Artemev, Ditmar, Eliseev, Kudriavtsev, Nikolaevski i , S. Obruchev,
Riabkin, and Tikhomirov.
The Kamchatka Peninsula is the only portion of the Asiatic mainland that
possesses active volcanoes. It is, therefore, natural that it should have
attracted geologists, Russians as well as others, for a considerable number
of years. The systematic geological investigation of the peninsula, however,
was undertaken only in connection with the post-Revolutionary coal and oil
prospecting program, at which time the study of the peninsula’s main volcanoes
also became systematic rather than haphazard. Consequently, the main features
of the geology of Kamchatka are now thoroughly known.
The Sredinny i (Central) Mountain Range constitutes the axis of the peninsula.
The outcrops along the crest of the rang consist of gneisses, micaschists,
thick phyllites, and Paleozoic argillaceous sandstones. The slopes consist

EA-I. Obruchev: Geology in of Siberia

of early and middle Mesozoic graywackes and shales (the Volcanic Series),
and Tertiary and Quaternary formations. Periodotites, pyro z x enites, and
some monzonites, outcrop between the sediments. The Paleozoic rocks are
intensely deformed; their folds strike almost north-south. The Mesozoic
rocks are less deformed and are less deformed and are cut by the necks of
extinct Tertiary volcanoes.
East of the longitudinal valley of the Kamchatka River (also under
systematic study) stand the peninsula’s eastern coastal mountains. Green
tuffaceous shales, the Bogachevka sandstone, four divisions of a Tertiary
sequence, dunites, pyro z x enites, and young extrusives comprise the dominant
rock types.
A broad belt of the western coastal plane is made up of five divisions
of a Tertiary sequence, the age of which ranges up to Pliocene. Those
sediments contain marine fossils and are covered by Quaternary sediments
and basalt flows. These lie upon a surface eroded upon metamorphic Paleozoic
rocks in the Sredinnyi Range, and upon Cenomanian and Turonian formations in
the Tigil area and at Cape Onman.
At Korf Gulf, in the extreme north, Mesozoic coal-bearing sediments
and extrusives are encountered. The coal and petroleum deposits of both
coasts have been studied repeatedly.
A great deal of attention has been paid to the study of the peninsula’s
volcanoes, particularly Mounts Kliuchevski i and Avacha. Mount Kluichevskii
has been under constant systematic study since 1938. Through investigations
have also been under constant systematic study since 1938. Thorough investi–
gations have also been made of the mineral springs, permafrost, past glaciations,
peat bogs, and soils. Paleontologists have studied the dominantly Cenozoic
fossil fauna and flora.

EA-I. Obruchev: Geology in of Siberia

The Kamchatka area was a geosyncline up until lower Carboniferous time;
then the sediments were thrown into folds which had a NNE.-SSW. strike.
These folds were eroded in Cretaceous times and the sea covered them again.
The present peninsula is the product of a series of tectonic movements,
which occurred between the Cretaceous and Quaternary periods, and which were
accompanied by igneous injection and extrusion along fault planes. The
earlier Quaternary lavas are basaltic and andesitic-basaltic; the later
Quaternary lavas are amphibolites-biotite-andesite.
Among the geologists who have studied the peninsula are Grechish, Dvali,
Diakov, Lazarenko, Morozov, Polevoi, and Shcherbakov. Vlodavets, Zavaritski i ,
Ivanov, Meniailov, and Novograblenov have played leading roles in volcanological
studies. Z e a varitski i , Krishtofovich, Tebenkov, Kharkhovich, and S h cherbekov
wrote general geological reports of the area.
In conclusion, we draw attention to the fact that, from time to time,
general accounts of the geology of all of Siberia have been compiled from
accumulated regional studies, just as general regional studies are based on
a synthesis of detailed local studies .

EA:I. Obruchev: Geology in of Siberia

BIBLIOGRAPHY

1. Arkhangelskii, A.D. Geologicheskoe Stroenie i Geologicheskaia Istoria SSSR.
(The Geological Structure and the Geological History of the U.S.S.R.)
Moscow, Leningrad, 1941. Vol.1.

2. -----, and Shatski, N.S. Kratkii Ocherk Geologicheskoi Struktury i Geologi–
cheskoi Istorii SSSR.
(Brief Outline of the Geological Structure
and the Geological History of the U.S.S.R.) Moscow, 1937.

3. Borisisk, A.A. Geologicheskii Ocherk Sibiri. (Geological Sketch of Siberia.)
Petrograd, 1923.

4. Edelshtein, I.S. “Geologicheskii ocherk Zapadno-Sibirskoi ravniny.”
(Geological sketch of the Wst Siberian plain.) Gosudarstvennce Russkoe
Geograficheskoe Obshchestvo, Zapadno-Sibirski Otdel, Omsk, Izvestiia
vol.5, 1925/ 1 2 6.

5. Iavorski, V.I., and Butov, P.I. “Kuznetskii Kamennougolnyi Bassein.”
(The Kuznetsk coal basin.) Russia. Geologicheski Komitet, St. Petersburg.
Trudy n.s., vol.177, 1927.

6. Mazarovich, A.N. Osnovy Geologii SSSR . (The Basic Elements of the Geology
of the U.S.S.R.) Moscow, 1938.

7. Nekhoroshev, V.P. Geherki po Geologii Sibiri . (Essays on the Geology of
Siberia.) Moscow, 1932.

8. Obruchev, S.V. Novaia Orograficheskaia Skhe n m a Severo-Vostochnoi Azii.
(New Orographic Outline of Northeastern Asia.) Leningrad, 1940.

9. ----. Ocherk Tektoniki Severo-Vostochnoi Azii . (Outline of the Techtonicas
of North-Eastern Asia.) Leningrad, 1938.

10. Obruchev, V.A. Geologia Sibiri . (Geology of Siberia.) Leningrad, Akademiia
Nauk, 1935-38. Vol.I: Dokembrii i Drevnii Paleozoi. (Pre-Cambrian
and Lower Paleozoic.) Vol.II: Srednii i Verkhnii Paleozoi. (Middle and
Upper Paleozoic.) Vol.III: Mezozoi i Kainozoi. (Mesozoic and
Cenozoic.)

11. ----. Geologicheskii Obzor Sibiri . (Geological Review of Siberia.) Moscow,
Goe.Izdat., 1927.

12. ----. Geologie von Sibirien . Berlin, Borntraeger, 1926. Fortschritte
der Geologie und Paleontologie . H.15.

13. ----. Istoriia Geologicheskogo Issledovaniia Sibir . (History of the
Geological Exploration of Siberia.) Moscow, Leningrad, Akedemiia
Nauk, 1931-47. Vol.I-V. (Still being published.)

V. A. Obruchev
HomeGeology of Siberia : Encyclopedia Arctica Volume 1: Geology and Allied Subjects
 Text Only
 Text & Inline Image
 Text & Image Viewer
 Image Viewer Only